Not exactly happy with the whole package once your boxers come off? You’re not alone: A sizable number of guys aren’t satisfied with some physical aspect of their junk—and that can influence how often they get busy under the sheets, a new study in the Archives of Sexual Behavior suggests.

In the study, researchers asked more than 4,100 men to report how they felt about certain physical aspects of their genitals. Then, they asked them questions about their sexual behavior to see if how they felt about their appearance influenced their sex lives.

Guys were most satisfied with the shape of the head of their penis and with their circumcision status. They felt pretty neutral about the scent of their genitals and their genital veins.

As for the issues plaguing the most guys? Twenty-seven percent said they were dissatisfied with the length of their flaccid penis, 19 percent were unhappy with the length of their erect penis, and 15 percent were displeased with the girth of their erect penis. (Find out how your penis size compares to average.)

The researchers discovered that while most men were reasonably satisfied with their genitals overall, 14 percent indicated they weren’t pleased with their junk, meaning they averaged a 3 or below on the 7-point scale that gauged satisfaction.

And it seems like that unhappiness carried over into the bedroom. Men who were dissatisfied with their genitals were less likely to report being sexually active than those who were fine with their junk.

They had less sex, too. For instance, 50 percent of men who were satisfied with their genitals reported experiencing weekly sexual activity, compared to 39 percent of men unhappy with what was below the belt. What’s more, the dissatisfied guys were also significantly less likely to be on the receiving end of oral sex.

It’s possible that lower satisfaction with your junk can cause anxiety in the bedroom, which may translate to poorer sexual function—making you more likely to shy away from sex, the researchers say.

When looking specifically at the drop in oral sex, the researchers believe that guys who are unhappy with their genitals may feel uncomfortable engaging in the act, which has been rated as more intimate than regular intercourse. (This intimate massage oil can help draw you closer together, too.)